What do splanchnic nerves innervate

Clinical anatomy of the splanchnic nerves. DOI: Download PDF. Splanchnic nerves are bilateral visceral autonomic nerves. The thoracic, lumbar and sacral splanchnic nerves are sympathetic in function while the pelvic splanchnic nerves are parasympathetic. These nerves have connections to the celiac, aortic, mesenteric, hypogastric and pelvic plexuses.

They control the functions of the gut and pelvic organs. Splanchnicectomies are sometime performed to alleviate intractable abdominal and pelvic pains. Keywords : splanchnic nerves, thoracic, lumbar, sacral, pelvic, nervi erigentes, splanchnicectomy.

The splanchnic nerves are bilateral autonomic nerves that supply abdominal and pelvic viscera. They are constituted of motor nerve fibers going to the internal organs visceral efferent fibers and sensory nerve fibers coming from these organs visceral afferent fibers. On each side of the human body, they include the thoracic splanchnic nerves greater, lesser and least or lowest , lumbar splanchnic nerve, sacral splanchnic nerve and pelvic splanchnic nerve nervus erigentis. All splanchnic nerves carry preganglionic presynaptic sympathetic fibers except for the pelvic splanchnic nerves that carry preganglionic parasympathetic fibers.

Splanchnicectomy is the procedure used mainly for the control of intractable visceral pain. Detailed knowledge of the anatomy and variations of the splanchnic nerves is mandatory for proper performance of splanchnicectomies Figure 1. The thoracic splanchnic nerves are made of the medial branches of the lower thoracic sympathetic ganglia.

Their formation and course are highly variable along their intrathoracic and subdiaphragmatic portions. Using a special stain and an image-analyser had revealed a decrease in the transverse area and perimeter of the unmyelinated axons the human LSN with the advance of age. This axon hypertrophy in the GSN was assumed to be a sort of compensation for the hypofunctions in the nervous control of abdominal organs. Most of the anatomy illustrations demonstrate the three thoracic splanchnic nerves piercing the diaphragmatic crura along three separate superoinferior sites.

However, a cadaveric human study has revealed that these three nerves most commonly pierce each diaphragmatic crus through a single location from which the three nerves then diverge to reach their destinations.

The celiac ganglion is a semilunar structure of small ganglionic masses connected together by nerve fibers. It lies on the crus of the diaphragm, on each side of the celiac arterial trunk.

The middle suprarenal artery traverses the celiac ganglion and the right ganglion lies behind the inferior vena cava. The thoracic splanchnic nerves and celiac ganglia play an essential role in pain management for upper abdominal disorders, particularly chronic pancreatitis and pancreatic cancer. Thoracoscopic splanchnic denervation TSD for chronic pancreatitis pain resulted in fewer patients on opioids and overall increases in pain thresholds.

The vascular relations of the right GSN trunk to the azygos vein particularly at its constitutive tributaries: ascending lumbar and subcostal veins and to the thoracic duct in the posterior mediastinum were investigated in human cadavers.

The average distances separating the right GSN from the azygos vein and the thoracic duct were 5. These great venous and lymphatic vessels related to the GSN have to be essentially respected at the time of celioscopic splanchnicectomy to avoid the risk of hemorrhage.

In adult pigs, there were sex and laterality differences of the thoracic splanchnic nerves. On the other hand, the ISN was present in The right thoracic splanchnic nerves were more cranial in origin, longer and larger than the left nerves.

No significant sex differences were determined. In addition, there were significant laterality differences regarding the origin and structure of these nerves even in the same rabbit. In Sprague Dawley rats, celiac ganglionectomy CGX through surgical removal of the celiac ganglionic plexus was performed with consequent significant reduction of the norepinephrine concentrations in the entire splanchnic area and the mesenteric vessels.

There was an abolishment of vasoconstriction of the mesenteric vessels in response to sympathetic nerve stimulation. These effects of CGX were mostly reversible as significant regeneration of sympathetic nerves in some organs was detected at five weeks after surgery. In immune challenges, the brain influences the immune function through a powerful neural reflex that suppresses the release of inflammatory factors Figure 2.

The least splanchnic nerve arises from branches of T The greater and lesser splanchnic nerves synapse at the celiac ganglion while the least splanchnic nerve ends by synapsing within the renal ganglion. The greater splanchnic nerve passes through the diaphragm by aortic hiatus and ends in the superior preaortic ganglia. The postsynaptic fibers then run toward the organs of the foregut, which is the celiac plexus.

It synapses with the aortic renal ganglia and the superior mesenteric ganglia. The greater splanchnic nerve plays a significant role in the inhibitory effects of the foregut. It leads to inhibition of the secretions and motility of the distal esophagus, stomach, and duodenum. Additionally, the greater splanchnic nerve causes inhibition of the bile emptying beside the inhibition of the contraction of the gallbladder smooth muscle, which leads to inhibits the pancreas to secrete their enzymes that stimulate glucagon release which leads to the inhibition of the insulin release.

Also, this nerve plays a role in the stimulation of glycogenolysis, gluconeogenesis, and glucose release. Eventually, this nerve innervates the capsule of the spleen, which is responsible for splenic pain.

This nerve also consists of paired nerves on each side of the human body that originates from the sympathetic branches of the L1 and L2 nerve roots. The postganglionic fibers innervate blood vessels in the same region as well as glands and smooth muscle.

The postganglionic sympathetic fibers vasoconstrict blood vessels, innervate and cause secretions from sweat glands, and contraction of the arrector pili muscles. The never fibers that supply the blood vessels of skeletal muscle cause vasodilatation.

Eventually, the fibers that reach the viscera regulate glandular secretions, allow for general vasoconstriction, and inhibit smooth muscle contraction of the gastrointestinal system. The postganglionic sympathetic fibers control the secretions from the sweat glands also give motor to arrector pili muscle by vasoconstrictor blood vessels, while the fibers that enter the skeletal muscle provide motor nerves by vasodilators. The sacral splanchnic nerves are paired nerves that run on each side of the human body.

These two parallel nerves form the inferior hypogastric plexus to join with the sacral part of the sympathetic trunk. The sacral splanchnic nerve gives both sensory and motor to the posterior aspect of the leg, foot, and the muscle and the skin of the pelvis. The main branches of this splanchnic nerve join and form parts of the superior, inferior gluteal, posterior cutaneous, sciatic, and finally, the pudendal nerves.

Each bundle contains 3, to 6, individual nerve fibers dispersed evenly in surrounding loose connective tissue. These nerves are responsible for the parasympathetic activity and nociception of the bladder, left colon, sigmoid colon, and rectum, and are at risk during any radical pelvic surgery.

During the fifth week of the development of the embryo, the neural crest cells form, and the cells migrate on both sides in the thoracic region of the spinal cord, creating paired cell masses which is dorsolateral to the aorta that called ganglia. All these sympathetic ganglia are joined in a bilateral chain by longitudinal nerve fibers, which are called sympathetic trunks along each side of the vertebral bodies. Plenty of neural crest cells relocate ventrally to the aorta to create neurons in the preaortic ganglia, such as the celiac and mesenteric ganglia.

Some sympathetic axons migrate to a paravertebral ganglion when they can synapse with neurons; also they may descend or ascend at other points to synapse in the trunk. Log In. Sign Up. Become a Gold Supporter and see no ads. Log in Sign up. Articles Cases Courses Quiz. About Recent Edits Go ad-free. Edit article. View revision history Report problem with Article. Citation, DOI and article data. Ariyasinghe, C. Parasympathetic pelvic splanchnic nerves. Reference article, Radiopaedia.

Urogenital , Gastrointestinal. URL of Article. On this page:. Last's anatomy, regional and applied. Churchill Livingstone. Read it at Google Books - Find it at Amazon 2. Clinically Oriented Anatomy, Sixth Edition.